DE10053037C1 - Preparation of silanes, useful as e.g. adhesion promoters or crosslinkers for polymers, uses dichloro-bis(diene-iridium) compound as catalyst and free diene as cocatalyst in the hydrosilylation of an alkene - Google Patents

Abstract

Preparation of silanes (I) with a (substituted) ethyl, higher alkyl or cycloalkyl-alkyl group, comprises reacting a tri-substituted silane (II) with an alkene (III) in the presence of a dichloro-bis(diene-iridium) compound (IV) as catalyst and free diene as cocatalyst. Preparation of silanes of formula (I) with a (substituted) ethyl, higher alkyl or cycloalkyl-alkyl group, comprises reacting a tri-substituted silane of formula (II) with an alkene of formula (III) in the presence of a dichloro-bis(diene-iridium) compound of formula (IV) as the catalyst, and free diene as a cocatalyst. R<6>R<5>CH-R<4>CH-SiR<1>R<23> (I) HSiR<1>R<2>R<3> (II) R<6>R<5>CH=CHR<4> (III) ((Diene))IrCl)2 (IV) R<1>, R<2>, R<3> = monovalent Si-C-bound 1-18C (halo)hydrocarbyl, Cl or 1-18C alkoxy; R<4>, R<5>, R<6> = H, monovalent 1-18C hydrocarbyl (optionally substituted by F, Cl, OR, NR2, CN or NCO), Cl, F or 1-18C alkoxy; or 2 of R<4>, R<5>, R<6> and the C atom(s) = cyclic group; R = H or monovalent 1-18C hydrocarbyl; and Diene = 4-50C hydrocarbon with >= 2 ethylenic C=C bonds, optionally substituted by F, Cl, OR, NR2, CN or NCO.

Description

The invention relates to a method for producing Organosilanes via hydrosilylation in the presence of Iridium compound as a catalyst and free diene as Cocatalyst.

Substituted alkylsilanes are extremely economical Interest in a variety of areas. you will be used z. B. as an adhesion promoter or as a crosslinker.

The platinum or rhodium catalyzed hydrosilylation of Unsaturated compounds have been widely studied Service. The product yields are often very high at 20 to 45% low, which is due to significant side reactions.

Iridium catalysts with diene ligands are 4658050 in the hydrosilylation of allyl compounds with Alkoxy-substituted silanes are used. JP-A-07126271 describes the hydrosilylation of allyl halides with Chlorodimethylsilane in the presence of iridium catalysts with dien ligands. Disadvantages of these methods are either moderate yields, an uneconomically high catalyst Concentration and / or a very short lifespan of the Catalyst.

The task was to create a catalyst system with a long life To develop a service life which has high product yields and purity guaranteed with very small amounts of catalyst and both continuous and discontinuous Reaction control allowed.

The invention relates to a process for the preparation of silane of the general formula I.

R ⁶ R ⁵ CH-R ⁴ CH-SiR ¹ R ² R ³ (I),

in the silane of the general formula II

HSiR ¹ R ² R ³ (II),

with alkene of the general formula III

R ⁶ R ⁵ CH = CHR ⁴ (III),

in the presence of iridium compound of general formula IV as a catalyst

[(Diene) IrCl] ₂ (IV),

and free diene is implemented as a cocatalyst, where
R ¹ , R ² , R ^{3 are} a monovalent Si-C-bonded, optionally halogen-substituted C ₁ -C ₁₈ -hydrocarbon, chlorine or C ₁ -C ₁₈ -alkoxy radical,
R ⁴ , R ⁵ , R ^{6 is} a hydrogen atom, a monovalent C ₁ -C ₁₈ -hydrocarbon, chlorine, fluorine or C ₁ -C ₁₈ alkoxy radical optionally substituted by F, Cl, OR, NR ₂ , CN or NCO , where in each case 2 radicals of R ⁴ , R ⁵ , R ⁶ together with the carbon atoms to which they are attached can form a cyclic radical,
R is a hydrogen atom, a monovalent C ₁ -C ₁₈ hydrocarbon radical and
Diene is a C ₄ -C ₅₀ hydrocarbon compound which is optionally substituted by F, Cl, OR, NR ₂ , CN or NCO and has at least two ethylenic C = C double bonds,
mean.

In the process, the target products of the general Formula I when using very small amounts of catalyst in Yields of at least 95% up to 98% obtained. Depending on  Area of application can therefore be a distillative Refurbishment can be dispensed with.

C ₁ -C ₁₈ hydrocarbon radicals R ¹ , R ² , R ^{3 are} preferably alkyl, alkenyl, cycloalkyl or aryl radicals. R ¹ , R ² , R ³ preferably have at most 10, in particular at most 6, carbon atoms. R ¹ , R ² , R ³ are preferably straight-chain or branched C ₁ -C ₆ -alkyl radicals or C ₁ -C ₆ -alkoxy radicals. Preferred halogen substituents are fluorine and chlorine. The radicals methyl, ethyl, methoxy, ethoxy, chlorine, phenyl and vinyl are particularly preferred as R ¹ , R ² , R ³ .

Hydrocarbon radicals R ⁴ , R ⁵ , R ^{6 are} preferably alkyl, alkenyl, cycloalkyl or aryl radicals. Preferably at most one of R ⁴ , R ⁵ , R ^{6 is} an alkoxy radical. R ⁵ , R ⁶ preferably have at most 10, in particular at most 6, carbon atoms. R ⁵ , R ⁶ preferably have at most 10, in particular at most 6, carbon atoms. R ⁵ , R ⁶ are preferably straight-chain or branched C ₁ -C ₆ -alkyl radicals or C ₁ -C ₆ -alkoxy radicals. The radicals R ⁵ , R ⁶ are particularly preferably hydrogen, methyl, ethyl, chlorine and phenyl.

Hydrocarbon radical R ⁴ preferably has at most 6, in particular at most 2, carbon atoms. The radicals R ⁴ are particularly preferably hydrogen, methyl, ethyl.

Hydrocarbon radical R preferably has at most 6, in particular at most 2 carbon atoms.

The hydrocarbon compounds used as diene can in addition to those having the ethylenic C = C double bonds Molecular units still alkyl, cycloalkyl or aryl units exhibit. The dienes preferably have 6 to 12 Carbon atoms. Mono- or bicyclic are preferred Serve. Preferred examples of dienes are butadiene, 1,3-  Hexadiene, 1,4-hexadiene, 1,5-hexadiene, isoprene, 1,3- Cyclohexadiene, 1,3-cyclooctadiene, 1,4-cyclooctadiene, 1,5- Cyclooctadiene and norbornadiene.

The diene in the catalyst of general formula IV and the free one serving as cocatalyst diene may be the same or be different. Preferably, both dienes are the same.

In a particularly preferred case, [(cycloocta-1c, 5c-diene) IrCl] _{2 is} used as the catalyst of the general formula IV and 1,5-cyclooctadiene is used as the cocatalyst.

The silane component of the general formula II is preferred in Excess of 0.01 to 100 mol% II, particularly preferably 0.1 up to 10 mol%, based on the alkene of the general formula III implemented. The iridium compound of the general formula IV is preferably in a concentration of 5 to 250 ppm, in particular 10 to 50 ppm, based on all in the reaction mix existing components. Diene is preferred in a concentration of 50 to 2500 ppm, in particular 50 to 1000 ppm, based on all present in the reaction mixture Components added as a cocatalyst.

The procedure can be in the presence or absence of aprotic solvents. If aprotic cal solvents are used are solvents or Solvent mixtures with a boiling point or boiling range of up to 120 ° C at 0.1 MPa is preferred. Examples of such Solvents are ethers, such as dioxane, tetrahydrofuran, diethyl ether, diisopropyl ether, diethylene glycol dimethyl ether; chlorinated hydrocarbons, such as dichloromethane, trichlor methane, carbon tetrachloride, 1,2-dichloroethane, trichlorethylene; Hydrocarbons such as pentane, n-hexane, hexane isomer mix, heptane, octane, benzine, petroleum ether, benzene, Toluene, xylenes; Ketones such as acetone, methyl ethyl ketone, di isopropyl ketone, methyl isobutyl ketone (MIBK); Esters, like Ethyl acetate, butyl acetate, propyl propionate, ethyl butyrate, ethyl isobutyrate;  Carbon disulfide and nitrobenzene, or mixtures this solvent.

This can also be used as an aprotic solvent in the process Target product of the general formula I can be used. This Process variant is preferred.

For example, the reaction components of the general Formula II together with iridium catalyst of the general Formula IV and optionally submitted to the diene and the Reaction component of the general formula III, if appropriate in Mixture with the diene, metered in with stirring. In another Variant is the target product of the general formula I together with catalyst of the general formula IV and optionally Diene submitted and a mixture of components II, III and if necessary, diene added. The response time to apply is preferably 10 to 2000 minutes. The reaction will preferably at a temperature of 0 to 300 ° C, in particular at 20 to 200 ° C. If necessary, also the Anwen suitable for increased pressure, preferably up to 100 bar.

The addition of the service also allows multiple implementations without Subsequent dosing of catalyst. Preferably Diene as a cocatalyst, especially continuously replenished.

All symbols above of the formulas above have theirs Meanings each independently.

In the following examples are, unless otherwise different indicated, all quantities and percentages by weight related, all pressures 0.10 MPa (abs.) and all temperatures 20 ° C.

Example 1 (embodiment I)

19.2 g (0.25 mol) of allyl chloride, 0.1 g (9.2. 10 ^-4 mol) of 1,5-cyclooctadiene and 3.0 mg were placed in a 100 ml three-necked flask equipped with an intensive cooler, internal thermometer and dropping funnel (4.5. 10 ^-6 mol) Di-µ-chloro-bis - [(cycloocta-1c, 5c-diene) - iridium (I)] submitted. At a bath temperature of 37 ° C, a mixture of 23.7 g (0.25 mol) of chlorodimethylsilane and 0.1 g (9.2. 10 ^-4 mol) of 1,5-cyclooctadiene over a period of 1.5 h added so that the internal temperature did not exceed 45 ° C. For the after-reaction, the mixture was kept at a bath temperature of 45 ° C. for a further hour. After working up by distillation, 40.8 g of chloro (3-chloropropyl) dimethylsilane were obtained, corresponding to a yield of 95% based on the silane.

Example 2 (Reusability of a Catalyst Batch)

Analogously to Example 1. Instead of working up by distillation, 19.2 g (0.25 mol) of allyl chloride and 0.1 g (9.2. 10 ^-4 mol) of 1,5-cyclooctadiene were added to the batch, and again a mixture of 23.7 g (0.25 mol) of chlorodimethylsilane and 0.1 g (9.2. 10 ^-4 mol) of 1,5-cyclooctadiene. The procedure was analogous to Example 1. The overall yield after distillation was 76.2 g (89%).

Example 3 (detection of the catalytic activity of the Distillation bottoms)

19.2 g (0.25 mol) of allyl chloride and 0.1 g (9.2. 10 ^-4 mol) of 1,5-cyclooctadiene were added to the distillation residue from Example 2, and again a mixture of 23.7 g (0.05 25 mol) of chlorodimethylsilane and 0.1 g (9.2. 10 ^-4 mol) of 1,5-cyclooctadiene. The procedure was analogous to Example 1. The yield after distillation was 37.0 g (87%).

Example 4 (Embodiment II)

Analogously to Example 1. In addition, 10.0 g (0.06 mol) of chlorine (3-chloropropyl) dimethylsilane presented as a solvent. To Distillation gave 48.8 g of product. After deducting the amount of 10.0 g used, the yield is 38.8 g corresponding to a yield of 91%.  

Example 5 (embodiment III)

Batch size as in Example 2. Chlorine- (3-chloropropyl) - dimethylsilane, catalyst and 1,5-cyclooctadiene were submitted and a mixture of allyl chloride, chlorodimethylsilane and 1,5-cyclooctadiene were added dropwise. After distillation, 50.1 g Received product. After deducting the amount of 10.0 g used the yield is 40.1 g corresponding to a yield of 94%.

Example 6 (Comparative Example with a Platinum Catalyst)

19.2 g (0.25 mol) of allyl chloride and 21.0 mg (3.1. 10 ^-5 mol, 125 ppm) of dichlorodicyclopentadiene platinum (II) were placed in a 100 ml three-necked flask equipped with an intensive cooler, internal thermometer and dropping funnel. submitted. 23.7 g (0.25 mol) of chlorodimethylsilane were metered in at a bath temperature of 37 ° C. The reaction was continued at 50 ° C. for 3 h. After working up by distillation, only 18.1 g (42%) of chloro (3-chloropropyl) dimethylsilane were obtained.

Example 7 (comparative example without addition of the cocatalyst)

Approach analogous to Example 1 without the addition of 1,5-cyclooctadiene. Even after a reaction time of 24 h, no measurable conversion was possible (NMR) can be determined.

Claims (9)

1. Process for the preparation of silane of the general formula I
R ⁶ R ⁵ CH-R ⁴ CH-SiR ¹ R ² R ³ (I),
in the silane of the general formula II
HSiR ¹ R ² R ³ (II),
with alkene of the general formula III
R ⁶ R ⁵ CH = CHR ⁴ (III),
in the presence of iridium compound of general formula IV as a catalyst
[(Diene) IrCl] ₂ (IV),
and free diene is implemented as a cocatalyst, where
R ¹ , R ² , R ^{3 are} a monovalent Si-C-bonded, optionally halogen-substituted C ₁ -C ₁₈ -hydrocarbon, chlorine or C ₁ -C ₁₈ -alkoxy radical,
R ⁴ , R ⁵ , R ^{6 is} a hydrogen atom, a monovalent C ₁ -C ₁₈ -hydrocarbon, chlorine, fluorine or C ₁ -C ₁₈ alkoxy radical optionally substituted by F, Cl, OR, NR ₂ , CN or NCO , where in each case 2 radicals of R ⁴ , R ⁵ , R ⁶ together with the carbon atoms to which they are attached can form a cyclic radical,
R is a hydrogen atom, a monovalent C ₁ -C ₁₈ hydrocarbon radical and
Diene is a C ₄ -C ₅₀ hydrocarbon compound which is optionally substituted by F, Cl, OR, NR ₂ , CN or NCO and has at least two ethylenic C = C double bonds,
mean. 2. The method of claim 1, wherein R ¹ , R ² , R ^{3 are} C ₁ -C ₆ alkyl radicals or C ₁ -C ₆ alkoxy radicals. 3. The method according to claim 1 or 2, wherein R ⁵ , R ^{6 are} C ₁ -C ₆ alkyl radicals or C ₁ -C ₆ alkoxy radicals. 4. The method according to claim 1 to 3, wherein R ^{4 is} selected from the radicals hydrogen, methyl, ethyl. 5. The method according to claim 1 to 4, wherein the temperature 0 is up to 300 ° C. 6. The method according to claim 1 to 5, wherein the increased pressure to 100 bar is applied. 7. The method according to claim 1 to 6, is used in the catalyst of the general formula IV [(Cycloocta-1c, 5c-diene) IrCl] ₂ . 8. The method according to claim 1 to 7, in which as a cocatalyst 1,5-cyclooctadiene is used. 9. The method according to claim 1 to 8, in which diene as Cocatalyst is continuously replenished.